Ignition system for internal combustion engines



Nov. 26, 1940. 4c. s. NAD'LER ET A1. 223,151

IGNAITION SYSTEM FOR INTERNAL COMBUSTlONv ENGINES Filed Dec. 30, 1959www WW ATTO R N EYS ,Mil

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Paf-entedNov. 26, 1940 lUNITED STATES IGNITION SYSTEM FOR INTERNALCOMBUSTION ENGINES Charles S. Nadler, Brooklyn, and Emil Kameny,

Richmond Hill, N. Y., assgnors to Standard Motor Products, Inc., LongIsland City, N. Y., a corporation of New York Application December` 30,1939, Serial No. 311,772 5 Claims. (Cl. 1 23-148) This invention relatesto a novel ignition system for internal combustion engines, and theobject and purpose of this invention is to provide means for deliveringto the engineduring the' starting operation a spark which is hotter andstronger than the normal running spark, including automatic controlmeans whereby a spark of the intensity vof the normal running spark isreestablished a short time after the engine has started and ismaintained during the period of engine operation. A further object is toprovide a hotter and stronger spark without the use of auxiliary relays,batteries or cells, and by use of a device which is compact,satisfactory for its itntended purpose, and inexpensive to manufacure. v

A-t the time of starting an internal combustion engine, in the wiringarrangements now in common use, the closing of the starting switchcauses a heavy drain on the batteries and consequently a considerabledrop in voltage across the battery terminals. .This condition continuesas long as the starting switch is closed. As a result, during thisperiod, the voltage applied to the ignition system is correspondinglyreduced and in consequence the ow of current in the primary windingofthe coil is of less intensity and the cur- -rent induced in thesecondary winding of the coil produces a weaker and thinner sparkwi-thin the cylinder. As is well known, the starting phase is the'timeat lwhich the strongest spark isrequire in the cylinder, because ofthe necessity oi `ig ting raw, cold, and overriched gasoline r mixture.

This invention is particularly directed to affording meansvformaintaining an increased current through the primary winding of the coilat the moment of starting and for such period of time vthereafteras toallow for delay inv ring and for the length of time which sometimes'elapses, 'particularly when engines are cold, during which they mustbecrankedlby the starter before combustion occurs. Furthermore, accordingto this invention, the length of time during which the spark ofincreased intensity is maintained can be established by the design andsize and relationship of the parts, so as to permit establishment "ofany desired length of time Within certain outside limits.' Fur-ther, theinvention affords means responsive to the temperaturejof the surroundingair, whereby the length of this period of intensified spark may beprolonged when the temperature of the surrounding air is low'andshortened when the temperature of the surrounding air is'high. Bythis means current intensication is afforded over a longer startingperiod when the weather is cold, and over a shorter starting period whenthe weather is warm, the latter saving unnecessary wear and tear on thepoints and condenser due to the intensiiiedl current.

Referring to the drawing which forms a part of this specification: 1

Fig. 1 shows diagrammatically the standard wiring circuit of theelectrical system of a. modern automobile, with the invention which isthe subject of this application incorporatedthereim Fig. 2 is -avertical section of a device embodying certainl elements of thisinvention Fig. 3 is a vertical elevation showing the device of Fig. 2-secured to the outer shell of anignition coil.

The one terminal of a battery IIl'is connected to a relatively heavycable II, the other end'of which is connected to one of the stationarycontacts ofa starter switch I2. The otherstationary contact of starterswitch I2 is connected to one terminal of the motor M, the otherterminal of which is connected to the ground. The opposite terminal ofthe battery is connected to the ground, thus a'ording a circuit wherebyenergy is transmitted from the battery through the closed starter switchI2 and through motor M and returned to ground. This circuit isclosedwhen the internal combustion engine is being. cranked toinducecombustion to begin in the cylinders.

Connected with some convenient point of the cable II is an ammeter I4.The'opposite terminal of the latter is connected with ignition switch I3and the opposite terminal of the latter is, in accordance withthisinvention, connected with terminal I5 of the device hereinafter tobe described. The opposite terminal I 6 of said device is connected tothe terminal I1 of a coil 2i, the opposite terminal I8 of which isconnected to one terminal of the interrupter I9. The opposite terminalof the interrupter islconnected to ground, and a condenser 2U isAbridged around the interrupter contacts in the usual well-known manner.Current flows in the circuit just de' scribed when the ignition switchI3 is closed and In. the primary ignition circuit, according to thepresent invention, there is'interposed a device comprising a ballastresistor '25, adapted to be normally connected in series with the other5 elements of the primary circuit described above, and, in associationtherewith, a heat-responsive -thermostaticswitch 26 bridging theterminals I5, I6 and, when closed, arranged to shunt the currentvthrough a path of low resistance around 10 the ballast' resistor 25, anda heating resistor 21 adapted to be energized when the ignition i switchI3 is closed, and spaced in such mechanical relationship (hereinaftermore fully described) with switch 26 as to afford a means for 1 causingsaid switch to open after expiration of a. period of time determined bythe heat output of heating resistor 21 and the rate of heat transferredfrom it to switch 26 at the prevailing temperature of the surroundingatmosphere,

,Referring to Fig. 2, switch 26 is preferably made of a bimetallic unitvcomprising two sheets or discs of metal having different coefcients ofexpansion, secured together and mounted upon a supporting post 28.Terminal members is, ls are positioned at either side of post 2s, theinner ends of these terminal members being formed as stationary lcontactelements adapted to engage either with the bimetallicunit or with raisedportions 29 secured thereon. Preferably the post 28 and the terminalsI5, I6 are secured in xed relation by being molded into a hardened block30 of molded insulating material such as, for example,phenolformaldehyde resin. Switch 26 is so arranged and adap-ted as toclose when the temperature in the neighborhood of the bimetallic unitfalls below a predetermined temperature, and to open' when saidtemperature rises above a predetermined temperature- In order to bringthe'hea-ting resistance 21 into 40 uitable relationship withthermostatic switch '26,

it is preferable to mount resistor 21 upon a spoolshaped member 3|,preferably of porcelain. For convenience, the ballast resistor 25 may besimilarly mounted upon a spool-shaped member 32, and both spools 3|, 32may ber supported upon a headed bolt 33 secured by a nut 34 tothe bottomof a container 35.'

The casing 35 may be made oi' sheet aluminum or other material having`heatconducting properties suited to the purpose. It is initially forniedwith a closed bottom and an open top. In the assembly thereof, bolt 33,with spools 3|, 32 thereon, is rst secured through .a central opening inthe bottom of the casing by means of the nut- 34, and suitableelectrical connections are provided for the resistors. Preferablyconnecting 'means are provided from terminal I5 to one end of' each ofresistors 25- and 21; the opposite end of resistor 25 is connected toterminal'IG and the opposite end of resistor 21 is connected to thecasing 35 which is grounded to the car chassis.

Casing35 may be formed vwith a circular indentation 36 serving as a seator rest for block 30, so arranged and positioned as to afford the .65-eXact desired spacing of switch 26 from heating it from turning. Tofurther secure the block in position, and to render the assemblywatertight, the upper edges 38 of the casing are then swaged over toassure a tight and permanent fit of the parts. A suitable mountingbracket 39 maybe 5 provided.

The result of the above construction is to form a small airtight chamberwithin casing 35 in which there is imprisoned a small body of air. Thetemperature of this air is responsive to heat 10 produced in the heatingresistor 21, as modified by greater or less loss of heat by conductionthrough the walls 35., For example, if the thermostatic switch 26 shouldbe arranged to remain closed so long as the temperature of the airaround it is below 100 F. and to open when the said temperature exceeds100 F., then in cold weather the heat produced in heating resistor 21would bring about a closing of switch 26 after a greater length of timethan it would in warm 20 weather.

Preferably, the parts are so arranged and related that at meantemperature the switch 26 will open approximately 20 seconds afterignition switch I3 has been closed, and that the length of this periodof time will be increased as the weather is colder and decreased as theweather is warmer l than the mean temperature.

Aprimary ignition circuit, including the primary winding of the coil andacross the interrupter contacts, and at the same time through theheating resistor 21 which is in parallel with the portions of theprimary ignition circuit mentioned. Assuming heating resistance 21 toVbe cold at the 40 time switch I3 is closed, thermostatic switch 26 istherefore closed, and the initial current directed through the primaryignition circuit will pass from terminal I5 through switch 26 toterminal I6, thus being shunted around the ballast 45 resistor 25.Accordingly, the full available voltage of the battery is impressedacross the primary winding of coil 2|, and this full available voltageis maintained until thermostatic switch 26 opens.

Upon the closingof ignition switch I3, current 50 flows through heatingresistor 21. Because of the mechanical arrangement of the parts alreadydescribed, and shown particularly'in Fig. 2, the heat produced byresistor 21 is 'communicated to the imprisoned body of air within casing35 and this 55 body of air rises in temperature at a rate governed to asubstantial degree by the rate of heat-loss through the walls of thecasing-i. e.,- by the temperature of the surrounding atmosphere. Whenthe imprisoned body of air in'the neighborhood U0 of the bimetallic unitreaches the critical temperature, switch 26 opens and thereby insertsballast resistor 25 into the circuit passing through the primary windingof coil 2|. When the ballast resistor 25 is so inserted in the ignitioncircuit, 65 a portion of the IR drop takes place within ballast resistor25, thereby reducing the voltage applied across the terminals of theprimary winding within the coil. As long as the ballast resistor 25remains in circuit, the voltagewithin 70 the coil. is reduced.

. The arrangement is, therefore, adapted to check excessive voltage inthe primary winding of the coil, and hence at the interrupter points andin the condenser, after a short period at to be connected in parallelwith said first-menstarting which may be longer in cold weather than inwarm weather; and to provide means whereby an intensified current ispassed through the primary winding of the coil and through the in--terrupter contacts, during this short period at starting. For practicalpurposes and at average temperatures, vwe have found that itis desirablethat such intensication of the currentv should be maintained forapproximately twenty seconds after the ignition switch has been closed.The mechanical arrangement of parts shown herein is conveniently adaptedto procure response of the thermostatic switch after approximately thatlength of time. -The arrangement is such that in cold weather, due torapid conduction of heat from'the body of air within casing 35 to theoutv side atmosphere, the period of response of thermostatic switch 26Ais lengthened, thereby resulting in a prolongation in cold weather ofthe period during which the ignition current is intensiiied.

While there is described herein 'one convenient form of device embodyingthis invention, and the one which is at present believed to be the bestform, it is our intention that this in vention` shall be deemed to coverand include all forms and shapes and sizes of device, whether the samebe located within or without the coil casing, as fall within the termsof the annexed claims.

We claim:

1. For use in an ignition system which includes an ignition switch acoil having a primary winding and a source ofelectrical current, thecombination` of a current-limiting resistor adapted to be connected inseries with the primaryv winding of said coil and to limit the flow ofcurrent through said winding when so connected, a thermo-responsiveswitch adapted to open when the temperature of the atmosphere in whichsaid switch is positioned increases above a predetermined temperatureand arranged, when closed, to conduct current to the primary winding ofsaid coil through a path having less resistance than is provided by saidcurrent-limiting resistor, and an electrical heating resistance adaptedvto be connected in parallel with the primary winding of said coil and tobe energized when said ignition switch is closed, said heatingresistance :being adapted to supply heat tending to raise thetemperature of the atmosphere in which said thermoresponsive switch ispositioned.

2. For use in an ignition system which includes a resistor, thecombination of a closed casing whose walls consist at least in part ofheat conducting material, a conned body of uid enclosed within saidcasing and in contact with the walls thereof, a' stationary switchcontact member, a thermo-responsive movable switch contact elementpositioned within said body of iluid and adapted to move relatively tosaid stationary contact member to separate said switch contact membersin response to increase in the temperature of the fluid in contact withsaid movable element above a predetermined temperature, and anelectrical heating resistance positioned within said body of fluid andadapted whenl energized tioned resistor and to dissipate heat into saidiiuid at a predetermined and substantially fixed rate, whereby actuationof said movable switch member will be delayed for a length of timeafterenergization of said resistance` dependent upon the rate of dissipationof heat from said fluid through the casing walls to the surroundingatmosphere.

3. For use in an ignition circuit which includes a source of electricalcurrent, an ignition switch, and the primary Winding of a coil, thecombination of a closed casing whose Walls consist at least in part ofheat-conducting material, a current-limiting resistor adapted to -bevconnected in said circuit in series with said primary winding when theignition switch is closed, a thermo-responsive switch positioned withinsaid casing and connected in parallel with said resistor and adapted tobe connected in series with said primary winding, and a heatingresistance positioned within said casing in thermal relationship withsaid last-mentioned switch, said heating resistance being adapted to beconnected acrossthe source of current in parallel with saidcurrent-limiting resistor and the primary winding of said coil when theignition switch is closed.

4. For use in an ignition circuit which includes a source of electricalcurrent, an ignition switch, and the primary winding of a coil, thecombination of a closed casing whose walls consist atleast in part ofheat-conducting material,

a current-limiting resistor adapted to be con' nected'in said circuit inseries with saidA primary winding when the ignition switch is closed, athermo-responsive switch positioned within said casing and connected inparallel with said resistor and adapted to be connected in series withsaid primary winding, saidv current-limiting resistor beingl positionedwithin said casing in Ithermal relationship with saidv last-mentionedsistor adapted to be connected in said 4circuit in series with saidprimary winding when the ignition switch is closed, a thermo-responsiveswitch positioned within said casing and connected in parallel with saidresistor and adapted to be connected in series with'said primarywinding, and a heating resistance positioned within said casing inthermal relationship with said last-mentioned switch, said heatingresistance being adapted to be connected across the source of current inparallel with the primary winding of said coil when the ignition switchis closed.

CHARLES S. NADLER.

EMIL KAMENY.

